Just noticeable difference (JND) refers to the maximum change magnitude that typical human visual system (HVS) cannot perceive. It reveals the visibility limitation of the HVS and reflects the underlying perceptual redundancy in visual signals, rendering it useful in many perceptual image/video processing applications such as image/video compression [1]}, [2]}, [3]}, [4]}, perceptual image/video enhancement [5]}, [6]}, information hiding and watermarking [7]}, [8]}, [9]}, [10]}, [11]}, [12]}, [13]}, and visual quality assessment [14]}, [15]}, [16]}, [17]}, [18]}, etc. Due to its wide applications, JND estimation of natural images has received much attention and been widely investigated. Generally, the JND models can be divided into two categories: JND models in pixel domain and JND models in frequency domain.
